Work transfer method for transfer press and work transfer apparatus for transfer press or press

Abstract

A work transfer apparatus for a transfer press or a press, with which an optimal die can be designed for each process, is provided. For this purpose, the work transfer apparatus for a transfer press includes at least a pair of lift beams ( 13 ), carriers ( 15 ) movable along a longitudinal direction of the lift beam, paired sub-carriers ( 50 ) movable in a carrier moving direction, power transmission means ( 51, 54 ) for transmitting carrier driving force to the sub-carriers, and a cross bar ( 17 ) which is laterally spanned between the sub-carriers and provided with work holding means ( 18 ) capable of holding a work.

1. A work transfer method for a transfer press, comprising:
 moving a pair of lift beams up and down, wherein the pair of lift beams are parallel to a work transfer direction; 
 reciprocatingly moving a cross bar based on a predetermined feed motion, wherein the cross bar is laterally spanned between a pair of carriers provided at the pair of lift beams to oppose each other, and wherein the cross bar is provided with a work holding unit for holding a work; 
 providing a carrier driving force directly to the carriers to move each carrier of the pair of carriers in a same moving direction along a longitudinal direction of the pair of lift beams; and 
 utilizing the movement of the pair of carriers to drive the cross bar to move to an offset position with respect to a moved position of the pair of carriers in a same direction as the direction of the movement of each of the pair of carriers. 
 
     
     
       2. The work transfer method for the transfer press according to  claim 1 , wherein the offset position is a position in which the cross bar is positioned beyond end portions of the pair of lift beams, when the pair of carriers are moved to substantially an end portion of the pair of lift beams in the longitudinal direction of the lift beams. 
     
     
       3. A work transfer apparatus for a transfer press, comprising:
 at least one pair of lift beams which are provided in parallel with a work transfer direction and which are movable up and down; 
 at least one pair of carriers which are provided at each of the at least one pair of lift beams, and which are movable along a longitudinal direction of the at least one pair of lift beams; 
 a pair of guides provided on at least one of the at least one pair of carriers; 
 a pair of sub-carriers which are provided on the pair of carriers along the pair of guides, and which are movable in a carrier moving direction; 
 a driving source to provide a carrier driving force directly to the carriers to move the carriers along the longitudinal direction of the at least one pair of lift beams; 
 a power transmission unit which transmits the carrier driving force to the pair of sub-carriers; and 
 a cross bar which is laterally spanned between each pair of sub-carriers, and which is provided with a work holding unit for holding a work; 
 wherein the carrier driving force is transmitted to the sub-carriers to move the cross bar and each of the sub-carriers to an offset position with respect to a moved position of the pair of carriers in a same direction as the moving direction of each carrier of the pair of carriers. 
 
     
     
       4. The work transfer apparatus for the transfer press according to  claim 3 , further comprising an additional cross bar laterally spanned directly between, an additional pair of carriers. 
     
     
       5. The work transfer apparatus for the transfer press according to  claim 3 , wherein the pair of guides protrude from end portions of the pair of lift beams in the carrier moving direction to guide the pair of sub-carriers, when the pair of carriers provided with the sub-carriers are moved up to substantially the end portions of the pair of lift beans in the, longitudinal direction of the pair of lift beams. 
     
     
       6. The work transfer apparatus for the transfer press according to  claim 3 , wherein the power transmission unit comprises:
 a first rack which is provided on a lift beam of the pair of lift beams provided with the sub-carriers along the longitudinal direction of the lift beam; 
 a first pinion which is meshed with the first rack and rotatably supported by a carrier of the pair of carriers on which the pair of sub-carriers are provided; 
 a second rack which is provided on a sub-carrier of the pair of sub-carriers along the longitudinal direction of the lift beam; 
 a second pinion which is meshed with the second rack and rotatably supported by the carrier; and 
 a rotational force transmission member which transmits a rotational force of the first pinion to the second pinion. 
 
     
     
       7. The work transfer apparatus of the transfer press according to  claim 3 , wherein the power transmission unit comprises:
 a rack which is provided on a lift beam of the pair of lift beams provided with the sub-carriers along the longitudinal direction of the lift beam; 
 a pinion which is meshed with the rack and rotatably supported by a carrier of the pair of carriers on which the pair of sub-carriers are provided; 
 a shaft which is rotatably supported at the carrier along the longitudinal direction of the lift beam, and which has a male thread on an outer circumference thereof; 
 a nut which is provided at a sub-carrier of the pair of sub-carriers, and which is screwed onto the shaft; and 
 rotational force transmission means for transmitting a rotational force of the pinion to the shaft. 
 
     
     
       8. The work transfer apparatus for the transfer press according to  claim 3 , wherein the power transmission unit comprises:
 a rack which is provided on the pair of lift beams provided with the pair of sub-carriers, along the longitudinal direction of the lift beam; 
 a pinion which is meshed with the rack and rotatably supported by a carrier of the pair of carriers on which the pair of sub-carriers are provided; 
 a deformation gear in which a teeth part of the gear is engraved on an outer arc portion of a sector, wherein the teeth part is meshed with one of the pinion and an idle gear for transmitting a rotational force of the pinion; 
 a rotary shaft provided at a center of the sector arc that is rotatably supported at the first carrier; 
 a first lever having a first end rotatably attached to a sub-carrier of the pair of sub-carriers, and a second end rotatably supported at the carrier, movably only in an up-and-down direction; and 
 a second lever having a first end fixed to the rotary shaft of the deformation gear, and a second end rotatably attached between the first end and the second end of the first lever by a shaft. 
 
     
     
       9. The work transfer apparatus for the transfer press according to  claim 3 , wherein said power transmission unit comprises:
 a rack which is provided at a lift beam of the pair of lift beams provided with the sub-carriers along the longitudinal direction of the lift beam, 
 a pinion which is meshed with the rack and rotatably supported by a carrier of the pair of carriers on which the pair of sub-carriers are provided; 
 a first pulley fixed to the pinion with a shaft; 
 second pulleys rotatably supported at both end regions of the carrier in the longitudinal direction of the lift beam; and 
 an endless belt which is wound around the first pulley and the second pulleys; 
 wherein a sub-carrier of the pair of sub-carriers is connected to the endless belt between the second pulleys. 
 
     
     
       10. A work transfer apparatus for a transfer press, comprising:
 at least one pair of lift beams provided in parallel with a work transfer direction to be movable up and down; 
 at least one pair of carriers which are provided at each of the at least one pair of lift beams, and which are driven by a linear motor to be movable along a longitudinal direction of the pair of lift beams: 
 a pair of guides provided on at least one of the at least one pair of carriers; 
 a pair of sub-carriers which are provided on the pair of carriers along the pair of guides, and which are movable in a carrier moving direction; 
 a driving source to provide a carrier driving force directly to the carriers to move the carriers alone the longitudinal direction of the at least one pair of lift beams; 
 a power transmission unit which transmits the carrier driving force to the pair of sub-carriers; and 
 a cross bar which is laterally spanned between the pair of sub-carriers, and which is provided with a work holding unit for holding a work; 
 wherein the carrier driving force is transmitted to the sub-carriers to move the cross bar and each of the sub-carriers to an offset position with respect to a moved position of the pair of carriers in a same direction as the moving direction of each carrier of the pair of carriers. 
 
     
     
       11. The work transfer apparatus for the transfer press according to  claim 10 , further comprising an additional cross bar laterally spanned directly between an additional pair of carriers. 
     
     
       12. The work transfer apparatus for the transfer press according to  claim 10 , wherein the pair of guides protrude from end portions of the pair of lift beams in the carrier moving direction to guide the pair of sub-carriers, when the pair of carriers provided with the sub-carriers are moved up to substantially the end portions of the pair of lift beams in the longitudinal direction of the pair of lift beams. 
     
     
       13. The work transfer apparatus for the transfer press according to  claim 10 , wherein the power transmission unit comprises:
 a first rack which is provided on a lift beam of the pair of lift beams provided with the sub-carriers along the longitudinal direction of the lift beam; 
 a first pinion which is meshed with the first rack and rotatably supported by a carrier of the pair of carriers on which the pair of sub-carriers are provided; 
 a second rack which is provided on a sub-carrier of the pair of sub-carriers along the longitudinal direction of the lift beam; 
 a second pinion which is meshed with the second rack and rotatably supported by the carrier; and 
 a rotational force transmission member which transmits a rotational force of the first pinion to the second pinion. 
 
     
     
       14. The work transfer apparatus for the transfer press according to  claim 10 , wherein the power transmission unit comprises:
 a rack which is provided on a lift beam of the pair of lift beams provided with the sub-carriers along the longitudinal direction of the lift beam; 
 a pinion which is meshed with the rack and rotatably supported by a carrier of the pair of carriers on which the pair of sub-carriers are provided; 
 a shaft which is rotatably supported at the carrier along the longitudinal direction of the lift beam, and which has a male thread on an outer circumference thereof; 
 a nut which is provided at a sub-carrier of the pair of sub-carriers, and which is screwed onto the shaft; and 
 rotational force transmission means for transmitting a rotational force of the pinion to the shaft. 
 
     
     
       15. The work transfer apparatus for the transfer press according to  claim 10 , wherein the power transmission unit comprises:
 a rack which is provided on the pair of lift beams provided with the pair of sub-carriers, along the longitudinal direction of the lift beam; 
 a pinion which is meshed with the rack and rotatably supported by a carrier of the pair of carriers on which the pair of sub-carriers are provided; 
 a deformation gear in which a teeth part of the gear is engraved on an outer arc portion of a sector, wherein the teeth part is meshed with one of the pinion and an idle gear for transmitting a rotational force of the pinion; 
 a rotary shaft provided at a center of the sector arc that is rotatably supported at the first carrier; 
 a first lever having a first end rotatably attached to a sub-carrier of the pair of sub-carriers, and a second end rotatably supported at the carrier, movably only in an up-and-down direction; and 
 a second lever having a first end fixed to the rotary shaft of the deformation gear, and a second end rotatably attached between the first end and the second end of the first lever by a shaft. 
 
     
     
       16. The work transfer apparatus for the transfer press according to  claim 10 , wherein said power transmission unit comprises:
 a rack which is provided at a lift beam of the pair of lift beams provided with the sub-carriers along the longitudinal direction of the lift beam; 
 a pinion which is meshed with the rack and rotatably supported by a carrier of the pair of carriers on which the pair of sub-carriers are provided; 
 a first pulley fixed to the pinion with a shaft, 
 second pulleys rotatably supported at both end regions of the carrier in the longitudinal direction of the lift beam; and 
 an endless belt which is wound around the first pulley and the second pulleys; 
 wherein a sub-carrier of the pair of sub-carriers is connected to the endless belt between the second pulleys. 
 
     
     
       17. A work transfer apparatus for a press for transferring a work within the press or between presses, comprising:
 at least one pair of lift beams which are provided in parallel with a work transfer direction and movable up and down, and which include a first lift beam provided on a left side of the work transfer direction and a second lift beam provided on a right side of the work transfer direction; 
 at least one pair of carriers which are provided at each pair of the at least one pair of lift beams, and which are movable along a longitudinal direction of the lift beams; 
 a pair of guides provided on at least one of the at least one pair of carriers; 
 a pair of sub-carriers which are provided along the pair of guides, and which are movable in a carrier moving direction; and 
 a cross bar which is laterally spanned between the pair of sub-carriers, and which is provided with a work holding unit for holding a work; 
 wherein the pair of guides, which guide the pair of sub-carriers, protrude from end portions of the pair of lift beams in the carrier moving direction, when the pair of carriers provided with the sub-carriers are moved up to substantially the end portions of the pair of lift beans in the longitudinal direction of the lift beams.